条件句中的虚拟语气用法大全
一、语气的分类
语气（mood）是一种动词形式，用以表示说话者的意图或态度。英语中的语气有三种：陈述语气、祈使语气和虚拟语气。
陈述语气主要用来表示所说的话是事实。
祈使语气主要用来表示所说的话是请求或命令。
虚拟语气（Subjunctive mood）主要用来表示说的话不是事实，或者是不可能发生的情况，而是一种愿望、建议或与事实相反的假设等。
二、虚拟语气在不同从句中的运用
虚拟语气可以用在状语从句和名词性从句中，名词性从句主要用在宾语从句和表语从句中，而状语从句主要用在条件状语从句中。接下去，我们就先来看看条件状语从句中的虚拟语气。
三、条件句中的虚拟语气
英语中的条件句分为真实条件句和非真实条件句。真实条件句一般采用“主将从现”的原则，而非真实条件句就是虚拟条件句，也就是我们接下来要梳理的条件句中的虚拟语气的用法。
（一）常规用法
根据条件句所针对的时间不同，条件句中的虚拟语气中其主句和从句的谓语动词要采用不同的形式。如下表：
如：
与现在事实相反：If I were you, I would go there tomorrow.
与现在事实相反：If he came to the party, I wouldn't come.
与过去事实相反：If she had been there, she would have met Jack.
与将来事实相反：If it were to rain tomorrow, they couldn't go for an outing.
与将来事实相反：If they should attend the meeting, we might get more support from them.
（二）混合条件句
有时条件从句中的动作与主句中的动作，发生的时间不一致，此时主从句的动词要根据它所针对的不同时间，采用不同的形式。但是，其基本用法还是基于第（一）条中常规用法的表格所列的内容。
比如：
If I were you, I wouldn't have been the party last night.
上句中的if条件句针对的时间是现在，所以be动词采用了与现在事实相反的形式were。但是，主句针对的时间是与昨天晚上的事实相反的，是过去的时间，所以动词要采用would have done的形式。
再比如：
If he had finished his homework earlier, he could be playing with his classmates now.
上句中的条件句针对的时间是过去的，所以动词采用了had done的形式。但是，其主句针对的时间是现在，所以动词采用了could be doing的形式。
（三）含蓄条件句
英语中有的条件不是通过if从句表达出来，而是包含在某些短语、上下文或其他方式中，其谓语也常用虚拟语气，我们把这种结构称为含蓄条件句。比如：
Without water, there would be no life.
But for the meeting, I would have gone home at the time.
It would be only partly right to follow in this way.
Having known in time ,we might have prevented the accident.
Givenmore attention, the tree could have grown better.
I was too busy at that time, otherwise/or, I would have called you.
上面句子中的粗体部分的介词短语、不定式短语、现在分词短语以及副词成分，就暗含了虚拟条件。
（四）条件句的倒装
在if引导的虚拟条件状语从句中，有时可以把虚拟条件中的连词if省去，而将had、should、were等助动词提到主语之前。如：
原句：If she were here, she would enjoy it.
去if：Were she here, she would enjoy it.
原句：If they had arrived, we could have set out earlier.
去if：Had they arrived, we could have set out earlier.
需要注意的是，如果条件句中本身没有助动词had、should、were，则该条件句不能采用省略if的倒装句。
（五）特殊条件句
在虚拟条件句中，需要注意以下句型：
If it were not for his presence, I would punish you. （要不是他在场，我会处罚你的。）
If it had not been for his help, I should have failed. （如果没有他的帮忙，我应该已经失败。）
这两句话中的条件句，也可以改为省略if的倒装句，即：
Were it not for his presence, I would punish you.
Had it not been for his help, I should have failed.
需要注意的是，两句话中的if it were not for和if it had not been for，其实都可以用without来替换，即：
Without his presence, I would punish you.
WIthout his help, I should have failed.
四、小试牛刀
接下来大家来看看你能做对几题：